Turbine housing for gas turbochargers

ABSTRACT

A turbine housing for exhaust gas turbochargers includes an outlet pipe and an external housing connected therewith. A rotor housing is disposed in the external housing and has a pipe-shaped neck operably coupled with the outlet pipe and axially displaceable relative to the same. A separate sealing ring is positioned operably between the neck and the outlet pipe, supported by the outlet pipe, and has an inwardly turned sealing portion sealingly and slidingly engaging the neck to form a secure gas seal therebetween.

CLAIM OF PRIORITY

Applicants hereby claim the priority benefits under the provisions of 35 U.S.C. §119, basing said claim of priority on German Patent Application Serial No. 10 2009025054.9, filed Jun. 10, 2009. In accordance with the provisions of 35 U.S.C. §119 and Rule 55(b), a certified copy of the above-listed German patent application will be filed before grant of a patent.

BACKGROUND OF THE INVENTION

The present invention relates to a turbine housing for exhaust gas turbochargers and the like.

Internal combustion engines for motor vehicles are increasingly charged by turbochargers in order to reduce fuel consumption. However, the weight of the exhaust system itself also affects fuel consumption. Turbochargers should therefore be as lightweight as possible. This need for a lightweight construction conflicts with the fact that when in use, turbochargers are subjected to significant mechanical stresses and especially extremely high thermal loads that demand a robust construction. Thermally induced stresses have a significant effect on the service life of a turbocharger. Thus, appropriate thermal compensating elements must be provided, although the same often have leaks. DE 100 22 052 A1, for instance, proposes to solve this problem by decoupling the components that conduct exhaust gas, and supporting and sealing the external structures. The arrangement depicted in DE 100 22 052 A1 makes it possible to connect the internal system to the external system in a sealed manner, but it does not address the thermal stress problems that occur, except by deforming the components. This results in the risk that the internal system or the rotor housing will collide with the turbine rotor.

In practice, however, it has been demonstrated that the internal system must also satisfy certain requirements in terms of tightness against leaks in order to assure that the turbocharger works efficiently. DE 103 52 960 A1 provides a number of options for solving the problem of tightness against leaks and simultaneous durability. More specifically, a sliding seat is disclosed that prevents the thermal stresses between the rotor housing and the overflow areas leading the exhaust gas to the outlet flange. DE 103 52 960 A1 indicates how the expansion can be compensated, but economic fabrication of the subject housing may be jeopardized by the thermomechanical loads that occur as result of this construction, by the required material properties, and by the production tolerances required for smooth operation.

SUMMARY OF THE INVENTION

Hence, an object of the present invention is to provide a turbine housing for an exhaust turbocharger which compensates for temperature expansion between the rotor housing and the exhaust gas outlet, has maximum sealing effect for the internal system, while at the same time uses very thin materials, and avoids welding in the sensitive outlet area of the rotor housing.

This object is attained using a turbine housing with the features in patent claim 1.

The inventive turbine housing for an exhaust gas turbocharger includes an external housing. A rotor housing having a pipe-shaped neck is arranged therein. The turbine housing furthermore includes an outlet pipe.

Exhaust gas can be conducted from the rotor housing towards an outlet flange via this outlet pipe. The outlet pipe can be displaced relative to the rotor housing to compensate for thermally induced longitudinal or axial expansion and contraction between the two parts. A separate sealing ring is provided between the neck and the outlet pipe, and can be connected to the outlet pipe as a separate component. The sealing ring seals the transition between the neck and the outlet pipe.

A distinctive aspect of the inventive turbine housing is that the sealing ring is turned inwardly. The sealing ring is pushed elastically over the outlet area of the neck, i.e., the internal system that conducts the exhaust gas. The sealing ring provides sealing, and renders the neck axially moveable or displaceable relative to the outlet pipe. The very good sealing effect achieved by the sealing ring configured in this manner is a result of the radially oriented elastic tension applied by the sealing ring to the outside surface of the neck. The high elasticity of the sealing ring results from the end thereof being turned inwardly.

The inward turning of the sealing ring end shall be construed to mean inverted across an angular area of at least 180°. The turned sealing ring end functions like a spring that resiliently urges the same axially under tension against the outside of the neck. It can be assured that the neck is positioned securely against the sealing ring, or the sealing ring against the neck, by using an expanding mandrel that is inserted into the neck after assembly to expand the neck. With this construction, it is also possible to use greater production tolerances with respect to the neck, because the sealing effect that is generated between the neck and the outlet pipe is attained by adjusting the sealing gap through use of the expanding mandrel.

The turned end of the sealing ring extends across an angular area of at least 180°. There is a line of contact between the neck and the sealing ring at an angle of 180°. The contact surface between the sealing ring and the neck is preferably disposed at a certain distance from the free end segment of the turned end to limit the material abrasion that can occur in an exhaust gas turbocharger when there are frequent axial displacements. It is therefore provided that the sealing ring has a free end segment on its turned end. This free end segment is expanded in a funnel shape. The free end segment is preferably at an angle of 5° to 20° to the outside of the neck. Thus, the free end segment forms a type of inclined or tapered lead-in surface that is located in front of the contact surface.

Thus, the sealing ring has a turned end, the contact surface immediately adjacent thereto, and the subsequent funnel-shaped expanded free end segment. The contact surface is at least annular, so that the contact surface is a line of contact with the neck. However, it can also be flat. In this case, the contact surface extends across a certain longitudinal segment of the neck, so that the actual sealing seat is not just annular, it is barrel-shaped.

The end of the sealing ring that faces away from the inwardly turned end fastens to the outlet pipe. The sealing ring can encompass the outside of the outlet pipe. The sealing ring can be fixed to the outlet pipe using thermal joining, such as soldering or welding. However, it is also possible to press fit the sealing ring to the outlet pipe using a support ring. However, the support ring can also be employed in combination with a thermal joining method, such as a fusion welding method, because the effects of the weld seam can be used, e.g. weld notches.

The sealing ring basically preferably comprises a metal material. There is some freedom in selecting the material because the sealing ring is a separate component that is joined to the outlet pipe. Thus, it is possible to employ particularly suitable materials, especially inexpensive materials. The sealing ring can comprise e.g. a nickel-based alloy.

In addition, the sealing ring can be made of a very thin-walled material. The thickness may be less than 1.0 mm. This has a positive effect on starting the catalytic converter.

The outlet pipe may be a integral component of a flange for connecting to the exhaust system, and therefore is generally thicker than the sealing ring. Because of this, fusion welding of the sealing ring and the outlet pipe may be improved by using a support ring that surrounds the sealing ring, in addition to the sealing ring. In this manner, components that essentially have the same thickness are welded to one another. This facilitates the welding due to more uniform heat input.

The support ring may also be embodied in a double layer to increase the thickness. This also further enhances the elastic properties of the sealing ring.

These and other advantages of the invention will be further understood and appreciated by those skilled in the art by reference to the following written specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention shall be explained in greater detail in the following using an exemplary embodiment that is illustrated in the drawings.

FIG. 1 is a section through a turbine housing; and

FIG. 2 is a detail of the sealing area in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in FIG. 1. However, it is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

FIG. 1 depicts a turbine housing 1 for an exhaust gas turbocharger. The turbine housing 1 includes an external housing 2 that extends from a housing flange 3 to an outlet flange 4. The external housing 2 is welded both to the housing flange 3 and to the outlet flange 4 and defines or delimits a gas-tight interior. A rotor housing 5 is disposed within external housing 2, and is formed from two sheet metal shells 6, 7 that are welded to one another on the outer circumference of the rotor housing 5. The sheet metal shell 7 depicted on the left has a tubular neck 8 that extends towards the outlet flange 4. A turbine rotor 9 projects into the neck 8. The contour of the neck 8 is adapted to the outer contour of the turbine rotor 9.

The neck 8 feeds the exhaust gas exiting from the rotor housing 5 via an outlet pipe 10 to the outlet flange 4, where the exhaust gas exits from the turbocharger 1. In the illustrated example, the outlet pipe 10 is an integral component of the outlet flange 4. The outlet pipe 10 is joined at its end that is adjacent to the neck 8 to a sealing ring 11 that surrounds the outside of the neck 8, as can be seen in the enlarged depiction in FIG. 2.

The sealing ring 11 has one end 12 that faces the neck 8 and is turned inwardly. Sealing ring 11 also has an opposite end 13 that faces the outlet pipe 10, surrounds the outside of the outlet pipe 10, and fixes the sealing ring 11 thereon. The end 13 of the sealing ring 11 on the outlet pipe side is surrounded by a support ring 14. The support ring 14, the end 13 of the sealing ring 11, and the outlet pipe 10 are welded to one another via a weld seam 15.

The sealing ring 11 initially extends cylindrically from the end 13 on the outlet pipe side towards the turned end 12. The turned end 12 is generally J-shaped, and is inwardly inverted or doubled over around 180°. The bend radius in the area of the turned end 12 corresponds to about half the thickness of the sealing ring 11, which is produced from a material with a thickness that is uniform. The thickness of the sealing ring 11 may be significantly thinner than the thickness of the outlet pipe 10.

A contact surface 16 is located on the turned end 12 of sealing ring 11. This contact surface 16 extends essentially parallel to the outer areas of the sealing ring 11, and is therefore somewhat barrel-shaped, and leads to a flat sealing seat that provides a very tight seal. A free end segment 17 of sealing ring 11 is connected to this contact surface 16. The free end segment 17 tapers or expands in a funnel shape. The angle “W” is from 5° to 20° to the outside 18 of the neck 8. The free end segment 17 terminates at a preselected distance from the end face 19 of the outlet pipe 10. The neck 8 also terminates at a preselected distance from the end face 19 of the outlet pipe 10. The distance is selected such that length compensation due to thermal expansion and contraction is possible with no problem under normal operating temperatures.

In the foregoing description, it will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.

LEGEND

-   1—Turbocharger -   2—External housing -   3—Housing flange -   4—Outlet flange -   5—Rotor housing -   6—Sheet metal shell -   7—Sheet metal shell -   8—Neck -   9—Turbine rotor -   10—Outlet pipe -   11—Sealing ring -   12—Flanged end -   13—End -   14—Support ring -   15—Weld seam -   16—Contact surface -   17—Free end segment -   18—Outside -   19—End face -   W—Angle 

1-10. (canceled)
 11. A turbine housing for exhaust gas turbochargers, comprising: an outlet pipe through which exhaust gas flows; an external housing connected with said outlet pipe; a rotor housing disposed in said external housing and having a pipe-shaped neck operably coupled with said outlet pipe and axially displaceable relative thereto; and a separate sealing ring disposed operably between said neck and said outlet pipe, being supported by said outlet pipe and having an inwardly turned sealing portion sealingly and slidingly engaging said neck to form a secure gas seal therebetween.
 12. A turbine housing as set forth in claim 11, wherein: said inwardly turned sealing portion of said sealing ring has a contact surface positioned abuttingly against an outside portion of said neck.
 13. A turbine housing as set forth in claim 11, wherein: said inwardly turned portion of said sealing ring is configured to apply radial tension to said neck.
 14. A turbine housing as set forth in claim 11, wherein: said inwardly turned portion of said sealing ring has a free end segment with a tapered funnel shape.
 15. A turbine housing as set forth in claim 14, wherein: said free end segment is disposed at an angle in the range of 5° to 20° relative to an outside portion of said neck.
 16. A turbine housing as set forth in claim 11, wherein: said sealing ring encircles said outlet pipe.
 17. A turbine housing as set forth in claim 16, including: a support ring surrounding said sealing ring; and a thermal fusion seam joining said support ring and said sealing ring to said outlet pipe.
 18. A turbine housing as set forth in claim 16, including: a clamp attaching said sealing ring to said outlet pipe.
 19. A turbine housing as set forth in claim 11, wherein: said sealing ring is constructed from a nickel-based alloy.
 20. A turbine housing as set forth in claim 11, wherein: said sealing ring has a double wall construction. 